SENA PS210W - Manual (Page 24)

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 Primary and Secondary DNS
The DNS (Domain Name System) server is used to locate and translate the correct IP address for a
requested web site address. A domain name is the web address (i.e. www. yahoo.com ) and is
usually easier to remember. The DNS server is the host that can translate such text-based domain
names into the numeric IP addresses for a TCP/IP connection.
The IP address of the DNS server must be able to access the host site with the provided domain
name. The Pro Series provides the ability to configure the required IP addresses of both the Primary
and Secondary DNS servers addresses. (The secondary DNS server is specified for use when the
primary DNS server is unavailable.)
3.1.3. Using DHCP
Dynamic Host Configuration Protocol (DHCP) is a communications protocol that lets network
administrators manage and automate the assignment of IP addresses centrally in an organization’s
network. DHCP allows the network administrator the ability to supervise and distribute IP addresses
from a central point and automatically send a new IP address when a computer is plugged into a
different network location.
When in static IP mode, the IP address must be entered manually at each computer. If a computer is
moved to another network location, a new IP address must be assigned. DHCP allows all the
parameters, including the IP address, subnet mask, gateway and DNS servers to be automatically
configured when the IP address is assigned. DHCP uses a “lease” concept in assigning IP
addresses to a computer. It limits the amount of time a given IP address will be valid for a computer.
All the parameters required to assign an IP address are automatically configured on the DHCP server
side, and each DHCP client computer receives this information when the IP address is provided at its
boot-up.
Each time the device is reset, the Pro Series broadcasts a DHCP request over the network. The reply
generated by the DHCP server contains the IP address, as well as the subnet mask, gateway address ,
DNS servers and the “lease” time. The Pro Series immediately places this information in its memory.
Once the “lease” expires, the Pro Series will request a renewal of the “lease” time from the DHCP
server. If the DHCP server approves the request for renewal, the Pro Series can continue to work
with the current IP address. If the DHCP server denies the request for renewal, the Pro Series will start
the procedure to request a new IP address from the DHCP server.
Note : While in DHCP mode, all network-related parameters for the Pro Series are to be configured
automatically, including the DNS servers